Interconnections for a substrate associated with a backside reveal

ABSTRACT

An apparatus relating generally to a substrate is disclosed. In this apparatus, a post extends from the substrate. The post includes a conductor member. An upper portion of the post extends above an upper surface of the substrate. An exterior surface of the post associated with the upper portion is in contact with a dielectric layer. The dielectric layer is disposed on the upper surface of the substrate and adjacent to the post to provide a dielectric collar for the post. An exterior surface of the dielectric collar is in contact with a conductor layer. The conductor layer is disposed adjacent to the dielectric collar to provide a metal collar for the post, where a top surface of each of the conductor member, the dielectric collar and the metal collar have formed thereon a bond structure for interconnection of the metal collar and the conductor member.

FIELD OF THE INVENTION

The following description relates to integrated circuit devices (“ICs”).More particularly, the following description relates to interconnectionsfor a substrate associated with a backside reveal.

BACKGROUND OF THE INVENTION

Microelectronic assemblies generally include one or more ICs, such asfor example one or more packaged dies (“chips”) or one or more dies. Oneor more of such ICs may be mounted on a circuit platform, such as awafer such as in wafer-level-packaging (“WLP”), printed board (“PB”), aprinted wiring board (“PWB”), a printed circuit board (“PCB”), a printedwiring assembly (“PWA”), a printed circuit assembly (“PCA”), a packagesubstrate, an interposer, or a chip carrier. Additionally, one IC may bemounted on another IC. An interposer may be an IC, and an interposer maybe a passive or an active IC, where the latter includes one or moreactive devices, such as transistors for example, and the former does notinclude any active device. Furthermore, an interposer may be formed likea PWB, namely without any circuit elements such as capacitors,resistors, or active devices. Additionally, an interposer includes atleast one through-substrate-via.

An IC may include conductive elements, such as pathways, traces, tracks,vias, contacts, pads such as contact pads and bond pads, plugs, nodes,or terminals for example, that may be used for making electricalinterconnections with a circuit platform. These arrangements mayfacilitate electrical connections used to provide functionality of ICs.An IC may be coupled to a circuit platform by bonding, such as bondingtraces or terminals, for example, of such circuit platform to bond padsor exposed ends of pins or posts or the like of an IC. Additionally, aredistribution layer (“RDL”) may be part of an IC to facilitate aflip-chip configuration, die stacking, or more convenient or accessibleposition of bond pads for example.

Conventionally, after an etch back for a backside reveal ofthrough-silicon vias (“TSVs”), a conformal dielectric coating isdeposited on the surfaces of the substrate and the revealed TSVs. Thisis followed by planarization to expose conductor vias of the TSVs and toplanarize the backside. After which, a metal layer may be deposited forinterconnection with the conductor vias. However, this conventionalapproach may have yield issues and/or cost issues, which make using itless desirable. Furthermore, this conventional approach may not besuitable for individual interconnections.

Accordingly, it would be desirable and useful to provide for postprocessing after a backside TSV reveal that improves yield, reducescost, and/or increases versatility for individual interconnections.

SUMMARY OF THE INVENTION

An apparatus relates generally to a substrate. In such an apparatus, apost extends from the substrate. The post includes a conductor member.An upper portion of the post extends above an upper surface of thesubstrate. An exterior surface of the post associated with the upperportion is in contact with a dielectric layer. The dielectric layer isdisposed on the upper surface of the substrate and adjacent to the postto provide a dielectric collar for the post. An exterior surface of thedielectric collar is in contact with a conductor layer. The conductorlayer is disposed adjacent to the dielectric collar to provide a metalcollar for the post, where a top surface of each of the conductormember, the dielectric collar and the metal collar have formed thereon abond structure for interconnection of the metal collar and the conductormember.

A method relates generally to processing a substrate. In such a method,obtained is the substrate having a post extending therefrom. The postincludes a conductor member. An upper portion of the post extends abovean upper surface of the substrate. A dielectric layer is deposited overthe upper surface of the substrate and the upper portion of the post. Anexterior surface of the post associated with the upper portion is incontact with the dielectric layer. The dielectric layer is disposed onthe upper surface of the substrate and adjacent to the post to provide adielectric collar for the post. A conductor layer is deposited over thedielectric layer. An exterior surface of the dielectric collar is incontact with the conductor layer. The conductor layer is disposedadjacent to the dielectric collar to provide a metal collar for thepost. A top surface of the conductive member is higher than a portion ofthe conductor layer. The substrate is polished to expose a top surfaceof the conductive member of the post. A bonding material is depositedonto the top surface of the conductive member and a top surface of eachof the dielectric collar and the metal collar, where the top surface ofeach of the conductor member, the dielectric collar and the metal collarhave formed thereon a bond structure for interconnection of the metalcollar and the conductor member.

Another method relates generally to processing a substrate. In such amethod, obtained is the substrate having a post extending therefrom. Thepost includes a conductor member. An upper portion of the post extendsabove an upper surface of the substrate. A dielectric layer is depositedover the upper surface of the substrate and the upper portion of thepost. An exterior surface of the post associated with the upper portionis in contact with the dielectric layer. The dielectric layer isdisposed on the upper surface of the substrate and adjacent to the postto provide a dielectric collar for the post. A conductor layer isdeposited over the dielectric layer. An exterior surface of thedielectric collar is in contact with the conductor layer. The conductorlayer is disposed adjacent to the dielectric collar to provide a metalcollar for the post. A top surface of the conductive member is higherthan a portion of the conductor layer. The conductor layer and thedielectric layer are etched to provide an opening and to expose the topsurface of the conductor layer. A bonding material is deposited into theopening, onto the top surface of the conductive member, onto a topsurface of the dielectric collar, and onto a top surface of the metalcollar, where the top surface of each of the conductor member, thedielectric collar and the metal collar have formed thereon a bondstructure for interconnection of the metal collar and the conductormember.

BRIEF DESCRIPTION OF THE DRAWINGS

Accompanying drawing(s) show exemplary embodiment(s) in accordance withone or more aspects of exemplary apparatus(es) and/or method(s).However, the accompanying drawings should not be taken to limit thescope of the claims, but are for explanation and understanding only.

FIG. 1A is a schematic diagram of a cross-sectional view depicting anexemplary portion of an in-process wafer for providing an integratedcircuit (“IC”).

FIG. 1B is a schematic diagram of a cross-sectional view depicting anexemplary portion of an in-process wafer for providing another IC.

FIG. 1C is the diagram of FIG. 1A with the IC vertically flipped afterchemical-mechanical-polishing of a lower surface of a substrate of theIC.

FIG. 1D is the diagram of FIG. 1A with the IC vertically flipped after abackside etch of a lower surface of a substrate of the IC to reveal alower end contact surface of a via conductor thereof.

FIG. 1E is the diagram of FIG. 1D with a lower surface of the IC havingformed thereon a passivation layer, which may be formed of one or moredielectric layers.

FIG. 2A is a block diagram of a cross-sectional view depicting anexemplary three-dimensional (“3D”) IC packaged component with viastructures.

FIG. 2B is a block diagram of a cross-sectional view depicting anotherexemplary 3D IC packaged component with via structures.

FIG. 3 is a block diagram of a cross-sectional view depicting anexemplary substrate of an in-process wafer.

FIG. 4A is a perspective view depicting an exemplary conductive member.

FIG. 4B is a perspective view depicting an exemplary post.

FIG. 5A is a block diagram of a cross-sectional view depicting a portionof the exemplary substrate of the in-process wafer of FIG. 3 aftersubsequent processing.

FIGS. 5B and 5C are respective enlarged views of a portion of thesubstrate of FIG. 5A.

FIG. 6 is a block diagram of a cross-sectional view depicting a portionof the exemplary substrate of the in-process wafer of FIG. 5A aftersubsequent processing.

FIG. 7 is a block diagram of a cross-sectional view depicting theexemplary substrate of FIG. 6 after subsequent processing.

FIG. 8A is a block diagram of a cross-sectional view depicting theexemplary substrate FIG. 7 after subsequent processing.

FIG. 8B is a block diagram of a top elevation view depicting theexemplary substrate of FIG. 7 after subsequent processing.

FIG. 9A is a block diagram of a cross-sectional view depicting anexemplary portion of the substrate of the in-process wafer of FIG. 3after subsequent processing and with a taller post.

FIG. 9B is a block diagram of a cross-sectional view depicting theexemplary portion of the substrate of FIG. 3 in FIG. 9A though with adifferent masking layer than that in FIG. 9A.

FIG. 10 is a block diagram of a cross-sectional view depicting thesubstrate of the in-process wafer of FIG. 9A after subsequentprocessing.

FIG. 11 is a block diagram of a cross-sectional view depicting thesubstrate of the in-process wafer of FIG. 10 after subsequentprocessing.

FIG. 12A is a block diagram of a cross-sectional view depicting thesubstrate of the in-process wafer of FIG. 11 after subsequentprocessing.

FIG. 12B is a block diagram of a cross-sectional view depicting thesubstrate of the in-process wafer of FIG. 9B after subsequentprocessing.

FIGS. 13A and 13B are respective block diagrams of a cross-sectionalview depicting the substrate of the in-process wafer of FIG. 12A afterdifferent types of subsequent processing.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following description, numerous specific details are set forth toprovide a more thorough description of the specific examples describedherein. It should be apparent, however, to one skilled in the art, thatone or more other examples and/or variations of these examples may bepracticed without all the specific details given below. In otherinstances, well known features have not been described in detail so asnot to obscure the description of the examples herein. For ease ofillustration, the same number labels are used in different diagrams torefer to the same items; however, in alternative examples the items maybe different.

FIG. 1A is a schematic diagram of a cross-sectional view depicting anexemplary portion of an in-process wafer for providing an IC 10component. IC 10 includes a substrate 12 of a semiconductor materialsuch as silicon (Si), gallium arsenide (GaAs), polymeric, ceramic,carbon-based substrates such as diamond, a silicon carbon (SiC),germanium (Ge), Si_(1-x)Ge_(x), or the like. Even though a semiconductorsubstrate 12 as provided from an in-process wafer is generally describedbelow, any sheet or layer semiconductor material or dielectric material,such as ceramic or glass for example, may be used as a substrate.Furthermore, even though an IC 10 is described, any microelectroniccomponent that includes one or more through-substrate via structures maybe used.

Substrate 12 includes an upper surface 14 and a lower surface 16 thatextend in lateral directions and are generally parallel to each other ata thickness of substrate 12. Use of terms such as “upper” and “lower” orother directional terms is made with respect to the reference frame ofthe figures and is not meant to be limiting with respect to potentialalternative orientations, such as in further assemblies or as used invarious systems.

Upper surface 14 may generally be associated with what is referred to asa “front side” 4 of an in-process wafer, and lower surface 16 maygenerally be associated with what is referred to as a “backside” 6 of anin-process wafer. Along those lines, a front-side 4 of an in-processwafer may be used for forming what is referred to as front-end-of-line(“FEOL”) structures 3 and back-end-of-line (“BEOL”) structures 5.Generally, FEOL structures 3 may include shallow trench isolations(“STI”) 7, transistor gates 8, transistor source/drain regions (notshown), transistor gate dielectrics (not shown), contact etch stop layer(“CESL”; not shown), a pre-metallization dielectric or pre-metaldielectric (“PMD”) 11, and contact plugs 9, among other FEOL structures.A PMD 11 may be composed of one or more layers. Generally, BEOLstructures 5 may include one or more inter-level dielectrics (“ILDs”)and one or more levels of metallization (“M”). In this example, thereare four ILDs, namely ILD1, ILD2, ILD3, and ILD4; however, in otherconfigurations there may be fewer or more ILDs. Furthermore, each ILDmay be composed of one or more dielectric layers. In this example, thereare five levels of metallization, namely M1, M2, M3, M4, and M5;however, in other configurations there may be fewer or more levels ofmetallization. Additionally, metal from a metallization level may extendthrough one or more ILDs, as is known. Furthermore, each level ofmetallization may be composed of one or more metal layers. A passivationlevel 13 may be formed on a last metallization layer. Such passivationlevel 13 may include one or more dielectric layers, and further mayinclude an anti-reflective coating (“ARC”). Furthermore, aredistribution layer (“RDL”) may be formed on such passivation level.Conventionally, an RDL may include: a dielectric layer, such as apolyimide layer for example; another metal layer on such dielectriclayer and connected to a bond pad of a metal layer of a lastmetallization level; and another dielectric layer, such as anotherpolyimide layer for example, over such RDL metal layer while leaving aportion thereof exposed to provide another bond pad. A terminal openingmay expose such other bond pad of such RDL metal layer. Thereafter, asolder bump or wire bond may be conventionally coupled to such bond pad.

As part of a FEOL or BEOL structure formation, a plurality of viastructures 18 may extend within openings formed in substrate 12 whichextend into substrate 12. Via structures 18 may be generally in the formof any solid of any shape formed by filling an opening formed insubstrate 12. Examples of such solid shapes generally includecylindrical, conical, frustoconical, rectangular prismatic, cubic, orthe like. Examples of openings for via structures, vias, and processesfor the fabrication thereof, may be found in U.S. patent applicationSer. No. 13/193,814 filed Jul. 29, 2011, and U.S. patent applicationSer. Nos. 12/842,717 and 12/842,651 both filed on Jul. 23, 2010, andeach of these patent applications is hereby incorporated by referenceherein for all purposes to the extent same is consistent with thedescription hereof.

Conventionally, via structures 18 may extend from upper surface 14 downtoward lower surface 16, and after a backside reveal, via structures 18may extend between surfaces 14 and 16, as effectively thickness ofsubstrate 12 may be thinned so as to reveal lower end surfaces of viastructures 18, as described below in additional detail. Via structures18 extending through substrate 12 between surfaces 14 and 16, thoughthey may extend above or below such surfaces, respectively, may bereferred to as through-substrate-vias. As substrates are often formed ofsilicon, such through-substrate-vias are commonly referred to as TSVs,which stands for through-silicon-vias.

Such openings formed in substrate 12 may be conformally coated,oxidized, or otherwise lined with a liner or insulator 15.Conventionally, liner 15 is silicon dioxide; however, a silicon oxide, asilicon nitride, or another dielectric material may be used toelectrically isolate via structures 18 from substrate 12. Generally,liner 15 is an insulating or dielectric material positioned between anyand all conductive portions of a via structure 18 and substrate 12 suchthat an electronic signal, a ground, a supply voltage, or the likecarried by such via structure 18 is not substantially leaked intosubstrate 12, which may cause signal loss or attenuation, shorting, orother circuit failure.

Overlying a liner 15 may be a barrier layer 24. Generally, barrier layer24 is to provide a diffusion barrier with respect to a metallic materialused to generally fill a remainder of an opening in which a viastructure 18 is formed. Barrier layer 24 may be composed of one or morelayers. Furthermore, a barrier layer 24 may provide a seed layer forsubsequent electroplating or other deposition, and thus barrier layer 24may be referred to as a barrier/seed layer. Moreover, barrier layer 24may provide an adhesion layer for adherence of a subsequently depositedmetal. Examples of materials that may be used for barrier layer 24include tantalum (Ta), tantalum nitride (TaN), palladium (Pd), titaniumnitride (TiN), TaSiN, compounds of Ta, compounds of Ti, compounds of Ni,compounds of Cu, among others.

Via structures 18 may generally consist of a metallic or otherconductive material generally filling a remaining void in an openingformed in substrate 12 to provide a via conductor 21. In variousexamples, a via conductor 21 of a via structure 18 may generally consistof copper or a copper alloy. However, a via conductor 21 mayadditionally or alternatively include one or more other conductivematerials such as tantalum, nickel, titanium, molybdenum, tungsten,aluminum, gold, or silver, including various alloys or compounds of oneor more of the these materials, and the like. A via conductor 21 mayinclude non-metallic additives to control various environmental oroperational parameters of a via structure 18.

Via structures 18 may each include an upper end contact surface 20 whichmay be level with upper surface 14 of substrate 12 and a lower endcontact surface 22 which may be level with lower surface 16 of substrate12 after a backside reveal. End surfaces 20 and 22 may be used tointerconnect via structures 18 with other internal or externalcomponents, as below described in additional detail.

In this example, upper end contact surface 20 of via conductors 21 areinterconnected to M1 through a respective contact pad 23. Contact pads23 may be formed in respective openings formed in PMD 11 in which M1extends. However, in other configurations, one or more via conductors 21may extend to one or more other higher levels of metallization throughone or more ILDs. Furthermore, via structure 18 is what may be referredto as a front side TSV, as an opening used to form via structure isinitially formed by etching from a front side of substrate 12.

However, a via structure may be a backside TSV, as generally indicatedin FIG. 1B, where there is shown a schematic diagram of across-sectional view depicting an exemplary portion of an in-processwafer for providing another IC 10. Fabrication of a backside TSV isgenerally referred to as a “via last approach,” and accordinglyfabrication of a front side TSV is generally referred to as a “viamiddle approach.”

IC 10 of FIG. 1B includes a plurality of via structures 18, which arebackside TSVs. For a backside TSV for via structure 18, liner 15 may bea deposited polymer into a “donut” silicon trench etch and deposited onlower surface 16 as a passivation layer 28, followed by a centralsilicon trench etch to remove an inner portion of the “donut” silicontrench, and followed by a seed layer deposition before patterning andelectroplating to provide via conductors 21 having respective solderbump pads or landings 29. Optionally, a conventional anisotropic siliconetch may be used prior to depositing and patterning a polymer isolationlayer as liner 15.

For purposes of clarity by way of example and not limitation, it shallbe assumed that front side TSVs are used, as the following descriptionis generally equally applicable to backside TSVs.

FIG. 1C is the diagram of FIG. 1A with IC 10 after achemical-mechanical-polishing (“CMP”) of a lower surface 16 of asubstrate 12. Such CMP may be performed to temporarily reveal lower endcontact surface 22, and thus portions of liner 15 and barrier layer 24previously underlying lower end contact surface 22 may be removed byCMP. Thus, in this example, lower end contact surface 22 may be coplanarand level with lower surface 16.

FIG. 1D is the diagram of FIG. 1A with IC 10 after a backside etch of alower surface 16 of substrate 12 to temporarily reveal a lower endcontact surface 22 of a via conductor 21. In this example, lower endcontact surface 22 may be coplanar with lower surface 16; however, asvia conductor 21, and optionally barrier layer 24, may protrude fromsubstrate 12 after a backside reveal etch, lower end contact surface 22in this example is not level with lower surface 16. For purposes ofclarity and not limitation, IC 10 of FIG. 1D shall be further described,as the following description may likewise apply to IC 10 of FIG. 1C.

FIG. 1E is the diagram of FIG. 1D with a lower surface 16 of a substrate12 having formed thereon a passivation layer 31, which may be formed ofone or more dielectric layers. Furthermore, passivation layer 31 may bea polymer layer. For example, passivation layer 31 may be abenzocyclobutene (“BOB”) layer or a combination of a silicon nitridelayer and a BCB layer. In some applications, passivation layer 31 may bereferred to as an inter-die layer. A metal layer 32, such as a copper,copper alloy, or other metal previously described, may be formed onpassivation layer 31 and on lower end contact surfaces 22 of viaconductors 21. This metal layer 32 may be an RDL metal layer. Balls 33may be respectively formed on bonding pads 34, where such pads may beformed on or as part of metal layer 32. Balls 33 may be formed of abonding material, such as solder or other bonding material. Balls 33 maybe microbumps, C4 bumps, ball grid array (“BGA”) balls, or some otherdie interconnect structure. In some applications, metal layer 32 may bereferred to as a landing pad.

More recently, TSVs have been used to provide what is referred to asthree-dimensional (“3D”) ICs or “3D ICs.” Generally, attaching one dieto another using, in part, TSVs may be performed at a bond pad level oran on-chip electrical wiring level. ICs 10 may be diced from a waferinto single dies. Such single dies may be bonded to one another orbonded to a circuit platform, as previously described. For purposes ofclarity by way of example and not limitation, it shall be assumed thatan interposer is used for such circuit platform.

Interconnection components, such as interposers, may be in electronicassemblies for a variety of purposes, including facilitatinginterconnection between components with different connectionconfigurations or to provide spacing between components in amicroelectronic assembly, among others. Interposers may include asemiconductor layer, such as of silicon or the like, in the form of asheet or layer of material or other substrate having conductive elementssuch as conductive vias extending within openings which extend throughsuch layer of semiconductor material. Such conductive vias may be usedfor signal transmission through such interposer. In some interposers,ends of such vias may be used as contact pads for connection of suchinterposer to other microelectronics components. In other examples, oneor more RDLs may be formed as part of such interposer on one or moresides thereof and connected with one or both ends of such vias. An RDLmay include numerous conductive traces extending on or within one ormore dielectric sheets or layers. Such traces may be provided in onelevel or in multiple levels throughout a single dielectric layer,separated by portions of dielectric material within such RDL. Vias maybe included in an RDL to interconnect traces in different levels of suchRDL.

FIG. 2A is a block diagram of a cross-sectional view depicting anexemplary 3D IC packaged component 50 with via structures 18. While astacked die or a package-on-package die may include TSV interconnects,use of via structures 18 for a 3D IC packaged component 50 is describedfor purposes of clarity by way of example. In this example of a 3D ICpackaged component 50, there are three ICs 10, namely ICs 10-1, 10-2,and 10-3, stacked one upon the other. In other implementations, theremay be fewer or more than three ICs 10 in a stack. ICs 10 may be bondedto one another using microbumps 52 or flip-chip solder bumps.Optionally, Cu pillars extending from a backside of a die may be used.Some of these microbumps 52 may be interconnected to via structures 18.For example, a Cu/Sn microbump transient liquid phase (“TLP”) bondingtechnology may be used for bonding ICs to one another. Thus,interconnect layers may be on one upper or lower side or both upper andlower sides of an IC 10 of a 3D stack.

A bottom IC 10-3 of such ICs in a 3D stack optionally may be coupled toan interposer 40. Interposer 40 may be an active die or a passive die.For purposes of clarity and not limitation, it shall be assumed thatinterposer 40 is a passive die. IC 10-3 may be coupled to interposer 40by microbumps 52. Interposer 40 may be coupled to a package substrate. Apackage substrate may be formed of thin layers called laminates orlaminate substrates. Laminates may be organic or inorganic. Examples ofmaterials for “rigid” package substrates include an epoxy-based laminatesuch as FR4, a resin-based laminate such as bismaleimide-triazine(“BT”), a ceramic substrate, a glass substrate, or other form of packagesubstrate. An under fill 53 for a flip chip attachment may encapsulateC4 bumps or other solder balls 53 used to couple interposer die 40 andpackage substrate 41. A spreader/heat sink (“heat sink”) 42 may beattached to package substrate 41, and such heat sink 42 and substratepackage 41 in combination may encase ICs 10 and interposer 40 of such 3Dstack. A thermal paste 42 may couple an upper surface of IC 10-1 on topof such 3D stack to an upper internal surface of such heat sink 42. Ballgrid array (“BGA”) balls or other array interconnects 44 may be used tocouple package substrate 41 to a circuit platform, such as a PCB forexample.

FIG. 2B is a block diagram of a cross-sectional view depicting anotherexemplary 3D IC packaged component 50 with via structures 18. 3D ICpackaged components 50 of FIGS. 2A and 2B are the same except for thefollowing differences; in FIG. 2B, another IC 10-4 is separately coupledvia microbumps 52 to interposer 40, where IC 10-4 is not coupled in thestack of ICs 10-1, 10-2, and 10-3. Furthermore, interposer 40 includesmetal and via layers for providing wires 47 for interconnecting ICs 10-3and 10-4. Furthermore, interposer 40 includes via structures 18 coupledto IC 10-4 through microbumps 52.

3D wafer-level packaging (“3D-WLP”) may be used for interconnecting twoor more ICs, one or more ICs to an interposer, or any combinationthereof, where interconnects thereof may use via structures 18.Optionally, ICs may be interconnected die-to-die (“D2D”) or chip-to-chip(“C2C”), where interconnects thereof may use via structures 18. Further,optionally, ICs may be interconnected die-to-wafer (“D2W”) orchip-to-wafer (“C2W”), where interconnects thereof may use viastructures 18. Accordingly, any of a variety of die stacking or chipstacking approaches may be used to provide a 3D stacked IC (“3D-SIC” or“3D-IC”).

FIG. 3 is a block diagram of a cross-sectional view depicting anexemplary substrate 100 of an in-process wafer. Substrate 100 includes aredistribution layer (“RDL”) or a back-end-of-line (“BEOL”) layer(“metal layer”) 101 interconnected to a plurality of vias 110 of asubstrate assembly 102. Substrate assembly 102 may be attached to asupport platform 120. Such attachment of support platform 120 isconventionally with an adhesive, so as to be able to remove supportplatform 120 later in the processing of a wafer. Accordingly, it shouldbe understood that upper or top surface 104 of a substrate layer 106 isan upper surface for a backside metal post reveal, and thus uppersurface 104 may optionally be thought of as a lower or bottom surface.However, for purposes of clarity and not limitation, surface 104 shallbe referred to as an upper surface hereinbelow.

For substrate assembly 102 having a silicon substrate layer 106, vias110 may be through-silicon-vias (“TSVs”). However, another type ofsemiconductor or a dielectric material may be used for substrate layer106 in other implementations. Thus, substrate layer 106 may, though neednot, be a portion of a slice or a slice of a single crystal of siliconas is common. Furthermore, vias 110 need not be through substrate vias,but may be posts located in and revealed to extend out of a substratelayer 106. Thus, for purposes of clarity and not limitation vias 110 arereferred to as posts. Along those lines, an upper or backside portion ofsubstrate layer 106 may be removed, such as by a backside etch forexample, to reveal or expose upper or bottom portions of posts 110.Again, for purposes of clarity and not limitation portions 105 of posts110 shall be referred to as upper or top portions.

Furthermore for purposes of clarity and not limitation, multiple layersbetween substrate layer 106 and metal layer 101 are not shown. However,it should be understood that substrate 100 may be an active die or apassive die for example. With respect to the latter, substrate 100 maybe a passive interposer.

Each post 110 includes a conductor member 112 and may optionally includeeither or both liner layer 109 and barrier and/or adhesion(“barrier/adhesion”) layer 111. Conventionally, a liner layer 109 isformed or deposited to line an inner surface of a hole followed bydeposition of a barrier/adhesion layer 111, which is then followed bydeposition of a metal layer to provide conductor member 112. Upperportions 103 of posts 110, which include upper portions 105, may includebarrier/adhesion layer 111 disposed on a top surface 107 of conductivemember 112, as well as a sidewall of conductive member 112, along with aliner layer 109 disposed on such portion of barrier/adhesion layer 111associated with upper portions 105. A conductive member 112 portionassociated with upper portion 105, as well as a barrier/adhesion layer111 portion and a liner layer 109 portion associated with upper portion103, may extend above or from an upper surface 104 of substrate layer106. For purposes of clarity and not limitation, a “via middle”formation is assumed in contrast to a “via last” formation. However, itwill be appreciated from the following description that either or both a“via last” and a “middle first” and via first formation may be used.

FIG. 4A is a perspective view depicting an exemplary conductive member112. Conductive member 112 may have a circular, elliptical, oval, squarewith rounded corners, rectangular with rounded corners, or othergeometric shape. For purposes of clarity and not limitation, conductivemember 112 is illustratively depicted as a cylindrical member with acircular top surface 107. Conductive member 112 may be imaged as asquare but printed as a square with rounded corners to the point ofappearing as a circle. Even though sidewall surface 201 of conductivemember 112 is illustratively depicted as being uniform, such sidewallsurface 201 may have roughness and may taper. Along those lines, bottomsurface 203 may have a larger cross-sectional area than top surface 107,as an etched hole or holes (“hole”) used to form a conductive member 112may be etched right-side up in reverse of the depiction in FIG. 4A.

FIG. 4B is a perspective view depicting an exemplary post 110. Afterforming a hole for formation of post 110, one or more liner andbarrier/adhesion layers, generally liner layer 109 and barrier/adhesionlayer 111, may be deposited to line such hole. In some applications, theliner 109 may be irrelevant and omitted between substrate 106 andconductor 110. With simultaneous reference to FIGS. 3, 5A, and 5B, post110 is further described. Such lined hole in substrate assembly 102 ofFIG. 3 may thus be filled with a conductive material (“a metal layer”)in order to provide conductive member 112. For a via last formation,conductive member 112 may line but not fill such etched holes. However,a middle first formation is assumed for purposes of clarity by way ofexample and not limitation. Along those lines, liner layer 109, as wellas barrier/adhesion layer 111, may have a respective top surface 212located above top surface 107 and a respective sidewall surface 211located outwardly from sidewall surface 201. Bottom surface 213, whichis a top surface when post 110 is initially formed, of both liner layer109 and barrier/adhesion layer 111 may be co-planar with bottom surface203 after completing front-side processing of post 110.

FIG. 5A is a block diagram of a cross-sectional view depicting a portionof the exemplary substrate 100 of the in-process wafer of FIG. 3 aftersubsequent processing. In FIG. 5A, only a single post 110 isillustratively depicted for purposes of clarity. However, it should beunderstood that substrate assembly 102 may have multiple posts 110.

FIG. 5B is an enlarged view of a portion 310 of substrate 100 of FIG.5A. With simultaneous reference to FIGS. 3, 4A, 4B, 5A, and 5B,formation of substrate 100 is further described.

A dielectric coating or layer 301 may be conformally or non-conformallydeposited onto top surface 104 of substrate layer 106, as well as anexterior surface of liner layer 109 to provide a dielectric layer for acollar. Optionally, an exposed portion of liner layer 109, as well as aportion of barrier/adhesion layer 111 underlying such portion of linerlayer 109, namely as associated with upper portion 103, may be removedprior to deposition of dielectric layer 301, and thus upper portion 105may be exposed for having dielectric layer 301 directly depositedthereon. In other implementations, liner layer 109 may be omitted, andso a barrier/adhesion layer 111 may be sufficient. In otherimplementations, liner layer 109 and barrier/adhesion layer 111materials may be similar materials, and in other implementations, theremay be no barrier/adhesion layer 111. Thus, dielectric layer 301 mayprovide a liner and/or barrier/adhesion layer or at least a level of abarrier. However, for purposes of clarity by way of example and notlimitation, it shall be assumed that liner layer 109 andbarrier/adhesion layer 111 as associated with upper portion 103 of FIG.3 are left in place when dielectric layer 301 is deposited. Thus,dielectric layer 301 may abut or otherwise be in contact with an exposedportion of sidewall surface 211 of liner layer 109 as associated withupper portion 103. As described below in additional detail, a portion ofdielectric layer 301 abutting such sidewall surface 211 of liner layer109 may provide a dielectric collar for post 110. Optionally, a highpressure plasma chemical vapor deposition (“CVD”) may be used to have athin sidewall or vertical surface deposition with respect to horizontalsurface deposition of a dielectric layer 301 for such non-conformaldeposition.

Optionally, another dielectric coating or layer 302 may be conformallyor non-conformally deposited onto a top surface of dielectric layer 301to provide a dielectric layer stack. More generally, one or moredielectric layers may be conformally or non-conformally deposited onto ametal post revealed backside of a substrate assembly 102 to provide adielectric collar for post 110. For example, dielectric layer 301 may bea thin dielectric layer of a silicon oxide or a silicon nitride, anddielectric layer 302 may be substantially thicker than dielectric layer301 and may be formed of a polymer, such as a polyimide for example.However, in other implementations, dielectric layers 301 and 302 may besimilar or the same material. For purposes of clarity and notlimitation, it shall be assumed that dielectric layers 301 and 302 areboth present and are both conformally or non-conformally deposited.

A conductor (“metal”) layer 303 may be conformally or otherwisedeposited onto dielectric layer 302. Along those lines, a portion ofmetal layer 303 is located below a top surface of 107 of conductivemember 112. In other words, a portion of metal layer 303 is locatedbelow upper portion 105. In another implementation, metal layer 303 mayinclude of one or more metal layers. Thus, while generally conformaldepositions of dielectric and metal layers have been described forpurposes of clarity, as long as a portion of metal layer 303 is belowupper portion 105, depositions other than or in addition to one or moreconformal or non-conformal depositions may be used. Furthermore, anexterior surface of dielectric layer 302, or dielectric layer 301 ifdielectric layer 302 is not used, may be in contact with an interiorsurface of metal layer 303 as associated with and spaced apart from asidewall surface portion of post 110. As described below in additionaldetail, a portion of metal layer 303 may thus provide a collar around orabout a dielectric collar or dielectric collars. Such metal collar maybe used as a solder scavenger collar for post 110.

Again, liner layer 109 may for example be a silicon oxide or a siliconnitride. Barrier/adhesion layer 111 may be Ta, TaN, or other suitablebarrier/adhesion layer as may depend upon the material used forconductive member 112. Conductive member 112 may be Cu, Al, W, or othermetal or a metal compound. Dielectric layers 301 and 302 may be asilicon oxide, a silicon nitride, a polymer such as polyimide, or BCBfor example. Metal layer 303 may be Cu, Al, W, or other metal or a metalcompound. These are just some examples of materials that may be used,and in other implementations, these and/or other materials may be used.Dielectric layers 301 and 302 may be the same or different materials.Along those lines, FIG. 5C is FIG. 5B though without dielectric layer302. Accordingly, dielectric layer 301 may be a polyimide with anadhesion promoter or BCB for example.

FIG. 6 is a block diagram of a cross-sectional view depicting a portionof the exemplary die 100 of the in-process wafer of FIG. 5A aftersubsequent processing. A top portion of in-process substrate 100 isremoved such as by chemical-mechanical-polishing (“CMP”) to provide agenerally planar surface 400. There may be some eroding around post 110of dielectric layers 301 and 302, as well as barrier/adhesion layer 111,as generally indicated as eroded out area 401. However, in otherimplementations, there may be little to no eroding. Thus, eroding may ormay not be present. After CMP, a top surface 408 of metal layer 303 maybe co-planar with a top surface 409 of conductive member 112. Recall,that an upper portion 105 of conductive member 112 was disposed above aportion of metal layer 303. Along those lines, after CMP, a portion ofmetal layer 303 may remain after polishing down an uppermost part ofconductive member 112. In another implementation, metal layer 303 maypatterned and processed for a distribution layer. Such an etchedpatterned metal layer 303 may be coated with a dielectric layer (notshown) prior to a CMP operation.

FIG. 7 is a block diagram of a cross-sectional view depicting theexemplary substrate 100 of the in-process wafer of FIG. 6 aftersubsequent processing. With simultaneous reference to FIGS. 3, 4A, 4B,5A, 5B, 6, and 7, formation of substrate 100 is further described.

A bonding material, such as solder, is deposited on a top surface 409 ofconductor member 112 to provide a bond structure 500. Metal layer 303may act as a seed layer for selective adherence of such bondingmaterial. Such bonding material may fill eroded out area 401, as well asoverlap 502 onto a collar portion of metal layer 303. Accordingly, a topsurface 409 of conductor member 112 and a solder scavenger collar hasformed thereon a bond structure 500 for interconnection of conductormember 112 and a metal collar formed of metal layer 303. Metal layer 303may further be for an RDL. A resist layer 501 may be deposited andpatterned to protect a collar portion of metal layer 303, as well asprotect bond structure 500 and an RDL interconnect portion of metallayer 303. Accordingly, an RDL may be patterned using resist layer 501.After masking with resist layer 501, an anisotropic or isotropic metaletch 503 may be used to remove a portion of unwanted metal layer 303.

FIG. 8A is a block diagram of a cross-sectional view depicting theexemplary substrate 100 of the in-process wafer of FIG. 7 aftersubsequent processing. FIG. 8B is a block diagram of a top elevationview depicting substrate 100 of the in-process wafer of FIG. 7 aftersubsequent processing. With simultaneous reference to FIGS. 3, 4A, 4B,5A, 5B, 6, 7, 8A, and 8B formation of substrate 100 is furtherdescribed.

After etch 503, resist layer 501 may be removed. One or more traces orstrips 611 of metal layer 303 may be part of an RDL, and a metal collar303C of metal layer 303, which may be used to scavenge solder, mayencircle, or more generally at least partially surround, post 110. Thus,a same mask used to form metal collar 303C may be used in the formationof an RDL. After etching with etch 503, a portion of a top surface 601of dielectric layer 302 may be exposed. Dielectric layers 302 and 301,as well as barrier/adhesion layer 111 and conductive member 112, may bedisposed under bond structure 500, and dielectric layers 302 and 301 mayprovide concentric dielectric collars 302C and 301C, respectively,within such a metal collar 303C. Thus, bond structure 500 may be used tointerconnect an RDL of substrate 100 to a conductive member 112 of apost 110 of such substrate 100. A polymer layer (not shown in thisfigure) may be deposited as a sold mask, where bond structure 500extends above such sold mask.

FIG. 9A is a block diagram of a cross-sectional view depicting anexemplary portion of substrate 100 of the in-process wafer of FIG. 3after subsequent processing and with a taller post 110. In other words,FIG. 9A is the block diagram of FIG. 5A with a taller post 110. Post 110of FIG. 9A for example may be approximately 1 to 20 microns higher thanupper surface 104 with respect to top surface 107, whereas post 110 ofFIG. 5A may be one or less than one micron tall measuring from topsurface 107 to upper surface 104. With simultaneous reference to FIGS.3, 4A, 4B, 5A, 5B, 8B, and 9A formation of substrate 100 is furtherdescribed.

A mask formed with resist layer 501 may be formed to protect an RDLportion of metal layer 303, as previously described, from etch 503, forinterconnection of metal collar 303C to such RDL with a bond structure500. An uppermost surface of resist layer 501 may be lower in elevationthan an uppermost thickness of metal layer 303. Optionally, depending onthe nature of the metal of such metal layer 303, masking may be avoidedat this juncture in favor of a blanket metal etch 503 to generallyremove horizontal structures of metal layer 303 while leaving generallyvertical structures of metal layer 303. Optionally, resist layer 501 maybe disposed on another side of post 110, such as if an RDL line wasbisected by post 110. If metal layer 303 and conductive member 112 areboth aluminum and/or tungsten for example, then contamination from suchmetal is less of an issue. If, however, if either or both of metal layer303 and conductive member 112 are copper, then silicon 106 may beprotected from copper contamination by an extension of a mask providedwith a resist layer 501, as generally indicated by dashed linestherefor, or optionally an etch stop layer (not shown). Accordingly,another mask may be used to pattern metal layer 303 underlying resistlayer 501 for forming an RDL. Optionally, resist layer 501 or other fillmaterial may be deposited to be co-planar with or just below, namely atleast approximately level with, top surface 107 of conductive member112, as generally indicated by dashed line 501D. Along those lines,rather than an etch 503, a CMP 503 may be used to remove material fromsubstrate 100 down to top surface 107.

FIG. 9B is a block diagram of a cross-sectional view depicting theexemplary portion of substrate 100 of FIG. 3 as in FIG. 9A though with adifferent masking layer than that shown in FIG. 9A. With simultaneousreference to FIGS. 3, 4A, 4B, 5A, 5B, 8B, 9A, and 9B formation ofsubstrate 100 is further described.

A mask formed with resist layer 501 may be formed to protect an RDLportion of metal layer 303, as previously described, from etch 503, forinterconnection of metal collar 303C to such RDL with a bond structure500. An uppermost surface of resist layer 501 may be higher in elevationthan an uppermost surface of metal layer 303 in order to perform a metaletch 503. Moreover, resist layer 501 may be disposed around post 110 todefine a hole 710. Optionally, resist layer 501 may be disposed furtheron another side of post 110, such as if an RDL line was bisected by post110, as generally indicated by dashed line 501Q.

Etch 503 may initially begin as a metal etch, but may be changed in situfor etching dielectric layers 302 and 301, as well as liner layer 109and barrier/adhesion layer 111, down to top surface 107 of conductivemember 112. An anisotropic dry etch may be used to form a hole, as wellas correspondingly remove exposed portions of metal layer 303,dielectric layer 302, and dielectric layer 301.

FIG. 10 is a block diagram of a cross-sectional view depicting theexemplary substrate 100 of the in-process wafer of FIG. 9A aftersubsequent processing. With simultaneous reference to FIGS. 3, 4A, 4B,5A, 5B, 8B, 9A, and 10 formation of substrate 100 is further described.After a metal etch 503, a top surface 601 of dielectric layer 302 may beexposed, and a taller metal collar 303C, as well as corresponding tallerdielectric collars 302C and 301C, from dielectric layers 302 and 301,may be disposed around post 110. A portion of metal layer 303, namelymetal layer 303R, for an RDL may remain as being contiguously connectedto metal collar 303C.

FIG. 11 is a block diagram of a cross-sectional view depicting substrate100 of the in-process wafer of FIG. 10 after subsequent processing. Withsimultaneous reference to FIGS. 3, 4A, 4B, 5A, 5B, 8B, 9A, 10, and 11formation of substrate 100 is further described.

A mask may be formed with a resist layer 901 to protect an RDL portionof metal layer 303R, metal collar 303C, dielectric collar 302C, anddielectric collar 301C. Optionally, resist layer 901 may be used toprotect a sidewall portion of barrier/adhesion layer 111, as well asgenerally horizontal structures of dielectric layers 302 and 301 notdisposed on top of post 110. Etch 902 may be performed by changingetches in situ to etch a hole down to a top surface 107 of conductivemember 112. Recall, no CMP to expose top surface is used in this flow,as was in the flow associated with FIG. 6.

FIG. 12A is a block diagram of a cross-sectional view depictingsubstrate 100 of the in-process wafer of FIG. 11 after subsequentprocessing. With simultaneous reference to FIGS. 3, 4A, 4B, 5A, 5B, 8B,9A, 10, 11, and 12A formation of substrate 100 is further described.Resist layer 901 has been removed, and a hole or opening 1001 down to atop surface 107 of conductive member 112 is formed. Opening 1001 mayhave a sidewall 1002 defined by layers 109, 111, 301, and 302.Optionally, resist layer 901 or other fill material may be deposited tobe co-planar with or just below top surface 107 of conductive member112, as generally indicated by dashed line 901D. Along those lines,rather than an etch 902, a CMP 902 may be used to remove material 1201from substrate 100 down to top surface 107. Thus, material 1201 abovesuch top surface 107 may be removed by such CMP to expose such topsurface 107 for forming an electrical contact thereto. After CMP, suchsacrificial resist layer 901 may be removed, and another resist mask maybe formed for forming an RDL or other upper metal layer. Optionally, ifthere are a sufficient number and density of posts for substrate 100, alow pressure CMP may be used to remove material 1201 without using asacrificial resist layer 901.

FIG. 12B is a block diagram of a cross-sectional view depictingsubstrate 100 of the in-process wafer of FIG. 9B after subsequentprocessing. With simultaneous reference to FIGS. 3, 4A, 4B, 5A, 5B, 8B,9B, and 12B formation of substrate 100 is further described. Resistlayer 501 has been removed, and a hole or opening 1001 down to a topsurface 107 of conductive member 112 is formed responsive to etchingresponsive to hole 710 defined by resist layer 501. Such etching mayinvolve a changing of etches, which changes may be done in situ. Opening1001 may have a sidewall 1002 defined by layers 109, 111, 301, 302, and303.

In this configuration of metal collar 303C, metal collar 303C may have aflare or flange 1003 directed outwardly, namely away from post 110, at abase or bottom portion of metal collar 303C, and dielectric collars 302Cand 301C may have corresponding flares. Moreover, in this configurationof metal collar 303C, metal collar 303C may have a shoulder or flange1004 directed inwardly, namely toward post 110, along a rim or topportion of metal collar 303C, which laterally extends inwardly towardhole 1001. Likewise, dielectric collars 302C and 301C may havecorresponding shoulders. Furthermore, exposed portions of layers 303,302, and 301 may be removed down to a top surface 104 of substrate layer106. A polymer solder mask layer (not shown) may be subsequentlydeposited, which acts as a passivation layer for substrate layer 106.

For purposes of clarity and not limitation, it shall be assumed thatsubstrate 100 of FIG. 12A is used for the following description.However, the following description equally applies to FIGS. 12A and 12B.

FIG. 13A is a block diagram of a cross-sectional view depictingsubstrate 100 of the in-process wafer of FIG. 12A after subsequentprocessing. More particularly, a bond structure material coating isdeposited to provide bond structure 500, such as previously described.Additionally, a polyimide layer or other solder masking material may bespun on or otherwise deposited to provide a solder mask 1101. In thisconfiguration, a dielectric layer formed of dielectric layers 301 and302 provides at least a portion of a sidewall 1002 of opening 1001, inwhich opening 1001 a portion of bond structure 500 is located. However,in the configuration of FIG. 12B, a dielectric layer formed ofdielectric layers 301 and 302, as well as metal layer 303, provides atleast a portion of a sidewall 1002 of opening 1001, in which opening1001 a portion of bond structure 500 is located.

FIG. 13B is a block diagram of a cross-sectional view depictingsubstrate 100 of the in-process wafer of FIG. 12A after subsequentprocessing using CMP. More particularly, a bond structure materialcoating is deposited to provide bond structure 500, such as previouslydescribed, for contact with top surface 107. Additionally, a polyimidelayer or other solder masking material may be spun on or otherwisedeposited to provide a solder mask 1101. In this configuration, adielectric layer formed of dielectric layers 301 and 302 does not have asidewall 1002 or opening 1001, and so bond structure 500 is located ontop surface 107, as well as top surfaces 1310 of each of dielectriclayers 301 and 302, metal layer 303, liner layer 109, andadhesion/barrier layer 111.

While the foregoing describes exemplary embodiment(s) in accordance withone or more aspects of the invention, other and further embodiment(s) inaccordance with the one or more aspects of the invention may be devisedwithout departing from the scope thereof, which is determined by theclaim(s) that follow and equivalents thereof. Claim(s) listing steps donot imply any order of the steps. Trademarks are the property of theirrespective owners.

What is claimed is:
 1. An apparatus, comprising: a post extending from asubstrate; the post including a conductor member and at least one linerlayer; an upper portion of each of the conductor member and the at leastone liner layer extending above an upper surface of the substrate; anexterior surface of the at least one liner layer of the post associatedwith the upper portion being in contact with a dielectric layer; thedielectric layer being disposed on the upper surface of the substrateand adjacent to the at least one liner layer to provide a dielectriccollar for the post; an exterior surface of the dielectric collar beingin contact with a conductor layer; the conductor layer being disposedadjacent to the dielectric collar to provide a metal collar for thepost; and a top surface of each of the conductor member, the at leastone liner layer, the dielectric collar and the metal collar beinggenerally co-planar and providing a generally planar surface with a bondstructure formed thereon for interconnection of the metal collar and theconductor member, and the metal collar not being in direct contact withthe at least one liner layer and not being in direct contact with theconductor member of the post.
 2. The apparatus according to claim 1,wherein the conductor layer is a redistribution metal layer.
 3. Theapparatus according to claim 1, wherein the post is of athrough-substrate-via.
 4. The apparatus according to claim 1, wherein:the post includes a barrier layer and a in addition to the at least oneliner layer; the barrier layer is disposed on a side surface of theconductor member; and the at least one liner layer is disposed on a sidesurface of the barrier layer.